There has been growing interest in the synthesis or organozirconium compounds owing to recent reports of their applications in bond-breaking reactions, insertion reactions, conjugate additions, olefin cross-coupling reactions, Grignard-type additions, and especially in their potential applications as catalysts for stereo- or regio-selective polymerizations of olefins.
1,1-Bimetallics of transition metals are well-known to serve a wide range of applications towards organic synthesis. However, the chemistry of 1,1-bimetallics containing zirconium has not been extensively studied, and only a few cases have been reported, including zirconium with zinc as well as aluminum. The examples of the use of boron in organic synthesis are legion. In order to extend organozirconiumboron chemistry, it would be of great value to develop a novel class of 1,1-bimetallics based on zirconium and boron. Since both zirconium and boron are lewis acids, it is reasonable to expect that zirconium and boron bimetallics could be potentially applied in organic synthesis as stoichiometric reagents and in polymerization of olefins as Lewis acid catalysts.
Thus, hydrozirconation is one of the most promising organometallic techniques used in organic synthesis. Schwartz and co-workers have developed this reaction in a series of papers as follows:
1. Schwartz, J.; Hart, D. W. J. Am. Chem. Soc. 1974, 96, 8115. PA0 2. Schwartz, J.; Labinger, J. A. Angew. Chem. Int. Ed. Engl. 1976, 15, 333. PA0 3. Hart, D. W.; Blackburn, T. F.; Schwartz, J. J. Am. Chem. Soc. 1975, 97, 680. PA0 4. Bertelo, C. A.; Schwartz, J. J. Am. Chem. Soc. 1976, 98, 262. PA0 5. Carr, D. B.; Schwartz, J. J. Am. Chem. Soc. 1979, 101, 3521.
It would be desirable to provide new bimetallic compounds containing Zr and B that provide superior and unexpected organic synthesis products and are useful as effective catalysts for the polymerization of alpha-olefins.